CSP Exam Prep: Cytomegalovirus (CMV)

Vocabulary practice flashcards covering cytomegalovirus (CMV) manifestations, pharmacology, dosing, resistance mechanisms, and monitoring parameters for the CSP exam.

Cytomegalovirus (CMV)

A double-stranded DNA herpesvirus that causes disseminated or localized end-organ disease in immunocompromised HIV patients, predominantly when CD4 counts drop below $50\,\text{cells/mm}^3$.

CMV Retinitis

The most common CMV end-organ disease in HIV patients, presenting as a necrotizing retinal infection characterized by fluffy, yellow-white retinal lesions, occasionally accompanied by hemorrhage.

CMV Colitis

A manifestation of cytomegalovirus infection that most commonly presents with diarrhea, fever, and anorexia, and carries a risk of complications such as gastrointestinal perforation and hemorrhage.

CMV Esophagitis

A clinical manifestation of cytomegalovirus characterized by odynophagia (pain with swallowing), nausea, and fever.

Immune Reconstitution Uveitis (IRU)

A form of immune reconstitution inflammatory syndrome (IRIS) that may occur following the initiation of antiretroviral therapy (ART) in patients with active or previous CMV retinitis.

Ganciclovir

A first-line antiviral agent for CMV retinitis dosed at $5\,\text{mg/kg}$ IV q12h for $14\text{--}21$ days induction; major adverse events include anemia, thrombocytopenia, neutropenia, and renal complications.

Valganciclovir

An oral prodrug used as first-line therapy for CMV retinitis (induction dose $900\,\text{mg}$ PO q12h for $14\text{--}21$ days) and the treatment of choice in pregnancy; must be administered with meals.

Foscarnet

An intravenous anti-CMV therapy active against ganciclovir-resistant strains; major adverse events include nephrotoxicity, electrolyte abnormalities, seizures, genital ulcers, and QT prolongation.

Cidofovir

An intravenous antiviral administered at $5\,\text{mg/kg/week}$ for 2 weeks, then every other week for CMV retinitis; requires mandatory pre-administration of hydration and probenecid to reduce nephrotoxicity risk.

Probenecid

An adjunctive medication required preemptively with cidofovir to decrease nephrotoxicity; contraindicated in patients with serious hypersensitivity and carries a theoretical cross-reactivity risk with sulfonamide allergies.

Letermovir and Maribavir

Antiviral therapies that are not recommended for CMV retinitis or CNS disease in people with HIV, as their use is largely limited to transplant populations.

G-CSF (Granulocyte Colony-Stimulating Factor)

A growth factor therapy that can be utilized to reverse neutropenia induced by ganciclovir treatment.

CMV UL97 Gene Mutation

A viral gene mutation that confers low-level resistance to ganciclovir in cytomegalovirus infections.

CMV UL54 Gene Mutation

A viral gene mutation that, when combined with UL97 mutations, causes high-level resistance to ganciclovir, as well as cross-resistance to foscarnet and cidofovir.

Ganciclovir Hematologic Safety Thresholds

Hematologic cutoffs below which ganciclovir is not recommended: absolute neutrophil count $< 500\,\text{cells/mm}^3$, hemoglobin $< 8\,\text{g/dL}$, or platelet count $< 25{,}000\,\text{cells/mm}^3$.

CMV Neurological Disease Induction Regimen

A combination induction therapy consisting of IV ganciclovir and IV foscarnet administered for 2 weeks or until the resolution of neurological symptoms.

Discontinuation Criteria for CMV Retinitis Maintenance

The clinical criteria allowing discontinuation of chronic maintenance therapy: CD4 count sustained at $> 100\,\text{cells/mm}^3$ for $3\text{--}6$ months on ART, receiving treatment for at least $3\text{--}6$ months, and documented inactive retinitis lesions.

Valganciclovir Food Effect

A pharmacokinetic interaction in which taking valganciclovir with a high-fat meal increases its systemic exposure (AUC) by $30\%$.

Intra-vitreous Injections (Ganciclovir / Foscarnet)

Direct ocular injections used adjunctively during induction for imminent sight-threatening CMV lesions to rapidly increase intraocular drug concentrations.

Tenofovir and Ganciclovir / Valganciclovir Interaction

A drug-drug interaction associated with reported cases of increased renal toxicity, mandating closer monitoring of renal parameters when co-administered.